Fix IP configuration in _create_lports routine
Fix IP configuration in _create_lports routine

Fix IP parsing/configuration in _create_lports routine since it
currently set the network address instead of a valid IP. E.g:
if the cidr is 192.168.0.1/24 and lport_amount is one, the configured
IP address will be 192.168.0.0
Moreover add the possibility to configure different IP addresses
belonging to the same subnet if _create_lports routine is run multiple
times in a row (e.g. using datapath context)

openvswitch/ovn-scale-test,openvswitch/ovn-scale-test